Blow-out preventer



Dec. 6, 1938. O c SNELL BLOW-OUT PREVENTER Filed Nov. 10, 1956 INVENTQR Patented Dec. 6, 1938 UNITED STATES PATENT OFFICE 2 Claims.

This invention relates to a blowout preventer.

The invention discloses certain improvements over that type of blowout preventer disclosed in copending application, Serial No. 10,640, filed March 12, 1935.

An object of the invention is to provide a blowout preventer adapted to be sectued to the top of a casing in a well bore and of such construction and design that the rams may be actuated by an operating fluid, and/ or by the fluid issuing under pressure from the well, into position to close the space between the casing and an inner pipe therein, in case a blowout occurs, provision being also made for actuating the rams into outer or inactive position, by suction.

With the above and other objects in view, the invention has particular relation to certain novel features of construction, operation, and arrangement of parts, an example of which is given in this specification and illustrated in the accompanying drawing, wherein:-

Figure 1 shows a vertical, sectional view of the preventer.

Figure 2 shows a cross sectional view taken on the line 2-2 of Figure 1.

Figure 3 shows a fragmentary side elevation of one of the rams employed, and

Figure 4 shows a plan View of a pump for operating the preventer.

Referring now more particularly to the drawing, the numeral I designates the housing as a whole which is adapted to be connected in any suitable manner, to the upper end of a well casing. The housing contains the upwardly con verging cylinders 2, 2 in which the rams 3, 3 are mounted.

At their upper ends the rams have the external longitudinal dove-tailed grooves 4, 4 therein and screwed through the cylinder walls are the externally threaded bolts 5, 5 whose inner ends are dove-tailed and project into the grooves 4 whereby the rams are held against turning in the cylinders but are permitted to move longitudinally therein into active or inactive positions.

The lower ends of the cylinders have the heads 6, 6 bolted or otherwise secured thereto.

Packing i is secured to the lower ends of the rams. Each packing contains the reenforcing plate 8 imbedded therein and has a clamp plate 9 abutting the outer end thereof. The packing assembly is secured to the outer end of each ram by set bolts as Ill.

On the upper ends of the rams are the halfround, complemental, packing assemblies II, I I, each composed of the upper and lower arcuate plates 12, I3 and the similarly shaped packing I4 between said upper and lower plates. These assemblies are maintained in assembled relation by the clamp bolts I5, I5. The upper ends of the rams have the radial dove-tailed grooves It, It and depending on the lower plates l3 are the dove-tailed tenons I I, I! which are located in corresponding grooves I6. The packing assemblies II are tapered on their outer sides to conform to the taper of the cylinders 2 and on their inner sides are shaped to seat closely about the drill stem, or other inner pipe I8, when the packing assemblies II are in active position. The inner sides of the upper ends of the rams 3 are correspondingly beveled and also vertically grooved to provide a passageway for the inner pipe I8 as clearly illustrated in the drawing. This passageway, at its lower end, is enlarged as at I9 to provide a seat for the coupling 2!! of the inner pipe I8 and to form the inside shoulders 2|, 2! against which the upper end of said coupling may abut when the rams are in active position to prevent the inner pipe from being expelled by internal pressure from the well.

Each head has a transverse bore 22, whose outer ends communicate with the passageways 23 leading outwardly from the interior of the housing I. Slidably mounted in the bores 22 are the plungers 24, 24 which are normally held in their outer positions by coiled springs 25, 25.

Inlet ducts 26, 26 lead inwardly from the bores 22 into the ends of the cylinders 2. These ducts are normally closed by the inwardly opening valves 21, 21. These valves have the outwardly extended stems 28 whose outer ends carry the stops 29 and surrounding said stems and interposed between the stops 29' and the inside annular shoulders 30, at the inner ends of the ducts 26, are the coiled springs 3! which normally hold said valves closed. The outer ends of the ducts 26 are normally closed by the plungers 24.

There is a control valve casing 32 containing a rotatable three-way valve 33, which may be manipulated in any conventional manner. Leading from the valve casing 32 there is a pressure line 34 having the branches 35, 35 which enter the outer ends of the cylinders 2 through the respective heads 6.

Entering the valve casing 32 from the pressure side of a suitable pump 36a there is a pressure line 36 and entering said casing from the suction side of said pump there is a suction line 31. The valve 33 may be turned into the position shown in the figure so as to connect the line 34 with the suction line 31 and a vacuum thus created in the outer ends of the cylinders 2 causing the rams to move, by suction, into outer, or inactive position away from the inner pipe l8. When moved into this position the packing assemblies I I may move slightly inwardly from the outer walls of the cylinders 2 so as to clear said walls. Said packing assemblies will thus be relieved of severe frictional contact with the plunger walls and will not be liable to adhere to the walls when in an inactive position as might otherwise happen particularly when subjected to high pressure when in inactive position.

The valve 33 may be turned, in an obvious manner, to connect the pipe 36 with the pipe 3t and to close the pipe 37 whereupon the slush, or other operating fluid will be forced under pressure into the outer ends of the cylinders 2 and the rams 3 will be thereby moved into active position so as to close the space around the inner pipe as is illustrated in the figure. When in this position the complemental packing assemblies H Will close closely about the inner pipe and the shoulders 2| will be in position to engage with the upper end of the coupling 20 beneath.

When the valve 33 is moved in position to close the suction pipe 31, gas or liquid issuing, under pressure from the well, will also pass through the channels 23 moving the plungers 24 outwardly to clear the ducts 26 and the fluid under pressure will lift the valves 2'! and pass into the cylinders and will assist in actuating the rams 3 into active position or in some cases may be suificient, unassisted, to accomplish that purpose and when the rams are in active position the well pressure may at times be suflicient to maintain them in said active position without assistance from the operating fluid. V

Should a blowout occur, the plungers 3, 3 may be moved to active'position either by a suitable manipulation of the valve 33 to permit the pumped liquid to be forced into the outer ends of the cylinders, as above explained, or the pressure fluid from the well may be suificient either when acting alone, or when acting in conjunction with the pumped liquid to accomplish the desired results.

The drawing and description disclose what is now considered to be a preferred form of the invention by way of illustration only, while the broad principle of the invention will be defined by the appended claims.

What I claim is:-

1. A blowout preventer comprising a housing having a vertical passageway therethrough for an inner pipe, said housing having cylinders, rams in the cylinders movable into active and into inactive positions, said rams being shaped to fit closely about the inner 'pipe when in active position, said housing having a passageway leading from the interior thereof into each cylinder, each cylinder having a bore and a plunger yieldingly mounted in the boreand having an inlet duct leading from the bore into the cylinder, an inwardly opening back pressure valve normally closing said duct, said plunger being mounted to be moved by the pressure of fluid from within the housing into position to clear the duct to permit the entrance of the pressurefluid into the cylinder and means for relieving the fluid from the cylinders to actuate the rams by suction into inactive position spaced away from the inner pipe.

A blowout preventer comprising a housing having a vertical passageway therethrough for an inner pipe, said housing having cylinders, rams in the cylinders movable into active and inactive positions, said rams being shaped to fit closely about the inner pipe when in said active position, means for admitting a pressure fluid from within the housing into the outer end of each cylinder, said means comprising a bore com municating with the interior of the housing, a

plunger in the bore, a duct leading from the bore into the cylinder, an inwardly opening back pressure valve controlling said duct, yieldable means in the bore normally holding said plunger in position to close said duct, said plunger and valve being movable under the influence of the pressure fluid in the housing to open position to admit the pressure fluid into the corresponding cylinder, and being effective to prevent its back flow and means for relieving the fluid from the cylinders to actuate the rams by suction into inactive position spaced away from the inner pipe.

OWENS 'C. SNELL. 

